• 3D FE tool for time dependent settlement predictions 

      Jostad, Hans Petter; Sivasithamparam, Nallathamby; Woldeselassie, B.H.; Lacasse, Suzanne (Chapter, 2016)
      A newly developed calculation tool for fully coupled general 3D finite element consolidation analyses is presented. The development has been part of an ongoing Research and Development project called GeoFuture and the tool ...
    • A macro-element for integrated time domain analyses representing bucket foundations for offshore wind turbines 

      Skau, Kristoffer Skjolden; Grimstad, Gustav; Page, Ana M.; Eiksund, Gudmund Reidar; Jostad, Hans Petter (Peer reviewed; Journal article, 2018)
      The paper presents a macro-element model for bucket foundations to be used in integrated time domain analyses of offshore wind turbines. The macro-element has been formulated in the multi-surface plasticity framework, and ...
    • A macro-element model for multidirectional cyclic lateral loading of monopiles in clay 

      Page, Ana M.; Grimstad, Gustav; Eiksund, Gudmund Reidar; Jostad, Hans Petter (Journal article; Peer reviewed, 2018)
      This paper investigates numerically the impact of multidirectional cyclic loads on the response of a monopile in clay supporting an offshore wind turbine (OWT). The results indicate that multidirectional loading modifies ...
    • A macro-element pile foundation model for integrated analyses of monopilebased offshore wind turbines 

      Page, Ana M.; Grimstad, Gustav; Eiksund, Gudmund Reidar; Jostad, Hans Petter (Journal article; Peer reviewed, 2018)
      The design of OWTs relies on integrated load analyses tools that simulate the response of the entire OWT (including the rotor-nacelle assembly, support structure and foundation) under combined aerodynamic and hydrodynamic ...
    • A New Foundation Model for Integrated Analyses of Monopile-based Offshore Wind Turbines 

      Page, Ana M.; Skau, Kristoffer Skjolden; Jostad, Hans Petter; Eiksund, Gudmund Reidar (Peer reviewed; Journal article, 2017)
      Offshore wind turbines are highly dynamic and tightly coupled systems subjected to variable cyclic loads. Designing and optimizing the support structure is a complex task, where several load scenarios have to be analysed ...
    • A numerical study of capacity and stiffness of circular skirted foundations in clay subjected to combined static and cyclic general loading 

      Skau, Kristoffer Skjolden; Chen, Ying; Jostad, Hans Petter (Peer reviewed; Journal article, 2017)
      Skirted foundations have been widely applied as offshore foundations for several decades. In design, the use of failure envelopes is convenient for assessing stability under combined loading. A large number of studies on ...
    • A procedure for predicting the permanent rotation of monopiles in sand supporting offshore wind turbines 

      Page, Ana M.; Klinkvort, Rasmus Tofte; Bayton, Steven; Zhang, Youhu; Jostad, Hans Petter (Peer reviewed; Journal article, 2020)
      Foundations for Offshore Wind Turbines (OWTs) are designed following the limit state philosophy. One of the considered states is the Serviceability Limit State (SLS), which verifies that the permanent rotation of the ...
    • An anisotropic shear strength model for cyclic accumulated plastic strain of overconsolidated clay 

      Cai, Fang; Eiksund, Gudmund Reidar; Grimstad, Gustav; Jostad, Hans Petter (Journal article, 2014)
      Many geotechnical problems involve calculation of the permanent deformation of overconsolidated clay under undrained cyclic loading. There are many existing methods in the literature which have been made for predicting ...
    • Correction factors for undrained LE analyses of sensitive clays 

      Fornes, Petter; Jostad, Hans Petter (Chapter, 2017)
      Reliable prediction of landslide triggering threshold and landslide run-out distance is essential for hazard risk assessment. The paper focuses on studying slides in sensitive clays, which represent a major geohazard in ...
    • Creep of geomaterials – some finding from the EU project CREEP 

      Grimstad, Gustav; Karstunen, Minna; Jostad, Hans Petter; Sivasithamparam, Nallathamby; Mehli, Magne; Zwanenburg, Cor; Evert, den Haan; Ghoreishian Amiri, Seyed Ali; Boumezerane, Djamalddine; Kadivar, Mehdi; Haji Ashrafi, Mohammad Ali; Rønningen, Jon A. (Peer reviewed; Journal article, 2017)
    • Design considerations of suction caisson foundations for offshore wind turbines in Southern China 

      Liu, Bo; Zhang, Youhu; Ma, Zhaorong; Andersen, Knut H; Jostad, Hans Petter; Liu, Donghua; Pei, Aiguo (Peer reviewed; Journal article, 2020)
      Suction caisson foundations are increasingly considered as a foundation solution for offshore wind farm development in China. This paper outlines the design considerations for developing a suction caisson supported jacket ...
    • Drainage conditions around monopiles in sand 

      Li, Shuzhao; Zhang, Youhu; Jostad, Hans Petter (Journal article; Peer reviewed, 2019)
      Large diameter monopiles are typical foundation solutions for offshore wind turbines. In design of the monopile foundations in sand, it is necessary to understand the drainage conditions of the foundation soil under the ...
    • Evaluation of soil models for improved design of offshore wind turbine foundations in dense sand 

      Jostad, Hans Petter; Dahl, Birgitte Misund; Page, Ana M.; Sivasithamparam, Nallathamby; Sturm, Hendrik (Peer reviewed; Journal article, 2020)
      In order to perform optimised and safe design of foundations for offshore wind turbines (OWT), it is important to have calculation tools that describe the key features of water-saturated soil subjected to complex and ...
    • GeoSuite Assistance for the Calculation of Settlement 

      Lacasse, Suzanne; Jostad, Hans Petter; Kim, Yunhee; Liu, Zhongqiang; Sandven, Rolf Birger (Chapter, 2016)
      As part of the development of the Norwegian-Swedish software GeoSuite, a module with geoassistance was developed and implemented. The paper describes this user-assistance, called "Wizard", helping the user with 1D, 2D and ...
    • GeoSuite – A Modular System for Geotechnical Design 

      Lacasse, Suzanne; Jostad, Hans Petter; L'Heureux, Jean-Sébastien; Torgersrud, Øyvind; Sandven, Rolf Birger (Chapter, 2016)
      Remarkable advances in the analysis tools of, for example slopes, embankment stability and settlements have happened since the 90s. Many are due to the information technology revolution in all aspects of geotechnical ...
    • Modelling of soil-structure-interaction for flexible caissons for offshore wind turbines 

      Skau, Kristoffer Skjolden; Jostad, Hans Petter; Eiksund, Gudmund Reidar; Sturm, Hendrik (Peer reviewed; Journal article, 2018)
      Published foundation models and procedures for calculation of caisson foundation response typically assume a rigid caisson in deformable soil. However, recent published measurement data from a prototype suction bucket ...
    • Numerical prediction and back-calculation of time-dependent behaviour of Ballina test embankment 

      Jostad, Hans Petter; Palmieri, Francesca; Andresen, Lars; Boylan, Noel (Peer reviewed; Journal article, 2017)
      The paper describes the Class A prediction and Class C back-calculations of the Ballina test embankment using the finite element program Plaxis and the Soft Soil Creep Model (SSCM). The prediction underestimated the measured ...
    • REDWIN – REDucing cost in offshore WINd by integrated structural and geotechnical design 

      Skau, Kristoffer Skjolden; Page, Ana M.; Kaynia, Amir M.; Løvholt, Finn; Norén-Cosgriff, Karin; Sturm, Hendrik; Andersen, H.S.; Nygaard, Tor Anders; Jostad, Hans Petter; Eiksund, Gudmund Reidar; Havmøller, O.; Strøm, P.; Eichler, D. (Peer reviewed; Journal article, 2018)
      The cost of offshore wind energy production has to be reduced continuously to improve its competitiveness compared to other energy sources. To contribute to this goal, a 4- year research project REDWIN – REDucing cost of ...
    • Stability analyses of quick clay using FEM and an anisotropic strain softening model with internal length scale 

      Grimstad, Gustav; Jostad, Hans Petter (Chapter, 2012)
      Sensitive soft clays generally display a significant post peak strain softening response under undrained deformation. A consequence of this behavior is that the safety factor during undrained stress changes cannot be ...